Using CaCl2

La(NO3)3 and Ce(NO3) 3 solutions

NaY was ion-exchanged to prepare CaY

LaY and CeY zeolites. Adsorptive removal of trace amount of 1

1-difluoro-2-chloroethylene (HCFC-1122) from 1

1

1

2-tetrafluoroethane product over NaY

CaY

LaY

and CeY zeolites were investigated. The structure and surface properties of fresh and regenerated adsorbents were characterized by X-ray diffraction

pyridine infrared spectra techniques and temperature programmed desorption of ammonia. Results show that the residual ratio of HCFC-1122 impurity in the eluate can be decreased to 1.0% over CaY，LaY and CeY zeolites via the formation of p-adsorption complexes between HCFC-1122 and Brønsted acid sites. The increase of intensity of Brønsted acid favors the formation of p-adsorption complexes

consequently decreasing adsorption temperature for complete removal of HCFC-1122 (CeY < LaY < CaY). Breakthrough adsorption capacity of HCFC-1122 at 220℃ increases in the order of CaY < LaY < CeY

since lower density of strong Brønsted and weak Lewis acid sites are favorable to lower degree polymerization initiated by p-adsorption complexes. The thermal regeneration of adsorbents is unsatisfactory

attributed to hardly removal of contaminant on the acid sites of saturated adsorbents during the thermal regeneration process.